Danny,
I had the same thought about getting larger wheels...also adding boat tie downs for more security. Yeah, I know about getting tires especially for trailers. Maybe the standard trailer/RV white spoke wheel would fit it. My first bid using uship.com was $2100.
The seller said he had towed it behind a Suburban from Illinois to Dallas with no problems. Dunno if he went slow however.
I do have a friend in Kerrville Tex who drives to Phoenix to see his folks. He's willing to tow it there and I could meet him. If this trailer will take the speed I think that would be the best way to go....and I get to see him in Phoenix and maybe shoot a silhouette match at Ben Avery